Fluid filter



'Ma T1T1937. R MEHL 2,079,807

FLUIDFILTER Filed July 2'7, 1954 BALSA WOOD INVENTOR ROBERT IKEHL ATTORNEY mired May 11, 1937 h v 2,079,807

, UNITED STATES PATENT OFFICE FLUID FILTER Robert J Kehl, Bayside, N. Y., assignor, by mesne assignments, to Union Carbide and Carbon Corporation, a corporation'of New York llpplication July 2'7, 1934;.Scrial No. 737,173

' scam (01.18344)" This invention relates to fluid filters and more and that balsa wood is especially effective in exparticularly to a filter construction and a filter tracting the small bits of carbon which may be material for use in removing-particles of foreign carried by acetylene and other fuel-gas. As is matter from a fiuid stream. The invention is Well. known, balsa wood has a very light and 5 especially useful in connection with the removal somewhat porous structure having innumerablev 6 of minute particles of foreign matter from a interstices which are arranged in no particular stream of gas,such as acetylene, flowing through form or pattern and which yet permit substana ,blowpipe conduit or passage. tially free passage of a gas or fluid therethrough, All blowpipes are subject to occasional back- Experiments have proved that balsa wood is un- 10 firing or popping. As a consequence of this acexpectedly more effective than other porous ma- 10 tion carbon in various degrees of fineness, some terials both organic. andinorganic, and actual of it almost in the amorphous state, is deposited tests have indicated the superiority ofthis main the passages of the blowpipe. Such deposits terial for the'stated purpose. Even after many of carbon are picked up by the fuel gas stream times the length of service possible with other and continue therewith in the direction of its screens it has been found that a balsa wood fil- 15 normal flow. Some of this carbon passes through ter is exceptionally effective in preventing pasthe protecting screens and builds up a'deposit sage of 'carbon'particle's therethrough, and that in ,or back of any metering or injecting orifices where discoloration of the orifices beyond the inthe line, the particles frequently proving to be balsa wood filter indicate that some carbon has i mutually adherent and forming a fluffy ball on passed the filter, no actual deposit of carbon can the'iinlet side of an orifice 'fwhich is peculiarly be' found in orabout the orifices. Furthermore, objectionable in the case of pilot lights through in certain types of service, it has been found dewhich the rush of fuel gas is necessary for proper sirable to insert one or more layers of felt or operation. Other particles of carbon adhere to other agglutinated fabric between two blocks of and clog the protecting screen or screens. balsa wood in forming the filter. It has been found that the screen or gauze A form of filter in which balsa wood blocks filter now generally used to protect orifices in vor discs are used is shown in the drawing formblowpipes, particularly in pilot light construcing a part of this specification. Referring now tions, become clogged in a comparatively short moreparticularly to the drawing, and especially so time and also that they fail to prevent clogging to Fig. 1, it will be seen that there is shown a of the orifices which they are designed to protect. pilot light nozzle I0 having a bore ll therein, Frequent disassembly of the pilot light apparatus and a restricted orifice l2 in this bore. Radial therefore becomes necessary with attendant expassages l3 extend through the nozzle to the pense and inconvenience. bore H on the exit side of the orifice l2, so that An important object of the present invention the stream of fuel-gas passing through the ori- 35 is, therefore, to provide a filtering material which fice aspirates into the bore l0 any fluid, such as will not become clogged with foreign particles, air, which may be present at the outer openings and which at the same time will prevent passage 7 of the passages l3. An externally threaded end of foreign particlesto passages beyond the filter, l5 of the nozzle I0 is screwed into a similarly and will not unduly restrict'the passage of the internally threaded counterbore IS in a conduit 40 fuel gas. A further object is the provision of a' member ll thereby attaching the nozzle to the simple and effective fluid filter having a small end of the conduit member. A cylindrical shield number of parts. 'Other objects will be apparent l8, internally threaded at one end, may be screwed upon consideration of the present specification. on external threads of the conduit member into 5 The invention is shown by way of illustration a position to protect the flame issuing from the in the accompanying drawing, in which: pilot nozzle I0. Radial ports IS in the shield Fig. l is a. longitudinal mid-section of a filter provide means'for the passage of combustion supconstructed in accordance with the invention, porting air to the flame issuing from the nozzle together with a pilot light assembly; and end; and other ports 20 allow passage of air Fig. 2 is a perspectiveview of one of the filto the air passages l3. A screen 2i may be held 50 tering elements. in place between the nozzle and the shield cover- As a result of many tests and much experiing the ports 20, to prevent foreign matter from mentation I have discovered that balsa ,yvood entering the passages l3. forms a filtering medium which is peculiarly ef- The conduit member I! has a longitudinal axfective in removing foreign particles from fluids; ial bore through it for passage of fuel-gas to the nozzle l0.

nects the sections 22 and 23. The function of the section 24 is that of providing an orifice of restricted cross-section which serves to regulate with reasonable accuracy the amount of low pressure gas passing to the nozzle 18.

The filter elements are held in place at the intake end of the conduit member H. A short tube section 25 having an end soldered, welded,.

or otherwise attached to the end of the conduit member I1, which is farthest from the nozzle [0, has an enlarged portion which is internally threaded at 26 and which has an annular shoula der 2? in which the threads'terminate. A nipple 28 has a similar enlarged section with external threads 29 thereon which are adapted to screw into the threads in the tube section 25. The nipple 28 has an internal annular shoulder 30 opposite the internal annular shoulder 2! of the short tube section for a purpose which will presently appear. The outer or intake end of the nipple 28 has a reduced internally threaded end 3| by which the nipple andall parts connected thereto may be joined to a fuel-gas supply line.

The filtering elements through which the fuelgas passes before reaching the nozzle ID are held in place between the annular shoulder 21 of the short tube section and the annular shoulder 30 of the nipple 28. The distance between the outer faces of the filtering elements or series of filtering elements being greater than the depth of the threads on the short tube section and the nipple, it is possible to holdlthe filtering elements tightly in place by screwing the nipple member tightly into the short tube section.

In many instances it has been found convenient to employ two blocks of balsa wood sepa rated by two thicknesses of felt or agglutinated fabric, and as here shown one block of balsa wood 32 in the form of a disc having a diameter equal to the internal diameter of the enlarged section of the nipple 28 abuts the annular shoulder 38 thereof, and two discs 33 and 34 of felt having an equal diameter separate the balsa wood disc 32 from a similar disc of balsa wood 35, which, in turn, abuts the internal annular shoulder 21 of the short tube section 25. The total depth of the filtering elements is such that the inner end of the nipple 28 will not reach the annular shoulder 2! of the short tube section when the former is screwed tight upon the latter. The filtering elements may thus be held firmly in place between the nipple and the tube section, and any fuel-gas passing through the end 3! of the nipple must pass through each of the filtering elements before entering the bore 23 of the conduit member IT. The orifices and passages of reduced section beyond the filter are thereby protected from'any solids in the fuel-gas of a size which is likely to clog them.

It will be appreciated that the blocks of balsa wood and the layers of felt may be cut' in different shapes and may be employed in filters of other form than that here shown and described.

It will also be appreciated that such filters may be employed for different purposes and different fluids without departing from the proper scope of the invention.

I claim:

1. A filter for removing carbon particles from acetylene gas,,including filtering material comprising a block of balsa wood. I

2. A filter for removing small particles from a fuel gas including filtering material comprising a plurality of separated blocks of balsa wood.

3. A filter for removing small particles from a fuel gas including filtering material comprising a plurality of blocks of balsa wood and at least one layer of agglutinated fabric spacing said blocks.

4. For use with a blowpipe subject to backfiring and utilizing a fuel gas which produces a deposit of carbon within the gas supply passage of the blowpipe during such backfiring, a filter comprising balsa wood adapted to arrest the flow of such carbonwith at least a portion of the fuel gas.

5. For use with a blowpipe and a burner utilizing a fuel gas, such blowpipe being subject to backfiring which produces a deposit of carbon within the gas supply passage of the blowpipe and the burner, a filter comprising balsa Wood adapted to arrest the flow of such carbon with the fuel gas passing to said burner.

' ROBERT J. KEHL. 

